uid=MCM,o=EDI,dc=edirepository,dc=org all public read phytprsn.dat Diane McKnight diane.mcknight@colorado.edu https://orcid.org/0000-0002-4171-1533 McMurdo Dry Valleys LTER http://mcmlter.org/ Inigo San Gil

Department of Biology, MSC03 2020 University of New Mexico Albuquerque NM 87131 US

(505) 277-2625 (505) 277-2541 isangil@lternet.edu data manager 2014-11-09 English

Using automated overwinter sampling devices, we collected preserved phytoplankton samples from multiple depths in Lake Fryxell, a permanently ice-covered lake in southern Victoria Land, Antarctica. Photosynthetic algae were maintained in a stable water column throughout winter darkness. The algal taxa overwintered in different ways in a species-specific manner. Typical vegetative cells were the most abundant form for all species found in the water column. Populations of one chlorophyte, Stichococcus sp., were observed in winter, but the species was absent in both summers. Two cryptophyte species were more abundant in winter than in summer. We interpret the increase in algal population size as evidence of heterotrophic growth in winter and of mixotrophic behavior throughout the year. For two chlorophyte species, some portion of the population had a distinctive morphology, for example, many Chlamydomonas subcaudata Wille. formed akinetes, whereas many Chlorella sp. contained a large amount of starch or other storage material. During winter, vegetative cells of the most abundant cyanobacterial species, Phormidium angustissimum West et West, occurred at the depth of the summer maximum and at depths below the oxycline. The presence of P. angustissimum below the oxycline may have resulted from the accumulation of settling cells at a depth with a greater density. In contrast to the settling of P. angustissimum, the general absence of the other algal species below the oxycline in winter indicated that these species were not influenced by overwinter settling.

algae lakes limnology phytoplankton LTER Controlled Vocabulary algae lake limnology phylum phytoplankton presence Station Keywords population dynamics LTER Core Areas Data contained in these files has been subjected to quality control standards imposed by the investigator. The user of this data should be aware that, while efforts have been taken to ensure that these data are of the highest quality, there is no guarantee of perfection for the data contained herein and the possibility of errors exists. If you encounter questionable data, please contact the MCM LTER data manager corrected or qualified. Thus, these data may be modified and future data will be appended.

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https://mcm.lternet.edu/content/summer-vs-winter-phytoplankton-presence-1989-1991 The Lake Fryxell basin is formed by a moraine depression in a wider portion of the Taylor Valley. It has a number of moraine islands and shallower areas, as well as several relatively well developed deltas. The lake is fed by at least 10 meltwater streams with a total drainage catchment of 230 km2. The lake is dammed to the southwest by the Canada Glacier and is topographically closed. It is perennially ice covered; during summer months, an ice-free moat generally forms around much of the lake margin. Lake levels have risen ~2 m between 1971 and 1996. There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 9 Maximum Length (km): 5.8 Maximum Width (km): 2.1 Maximum Depth (m): 20 Surface Area (km^2): 7.08 Ice Thickness Average Surface (m): 3.3 - 4.5 Volume (m^3 * 10^6): 25.2 163.048782348633 163.259582519531 -77.597076416016 -77.622711181641 18 18 meter 1989-01-01 1991-12-31 In 2015, Inigo San Gil renamed the data-source to LIMNO_PHYTO_PRESENCE_SUM_WIN (formerly was phytprsn) to make it coherent with the database stored data. At the same time, some enhancements to the variables definitions were introduced. Data and metadata were migrated to DEIMS. McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER

LIMNO_PHYTO_PRESENCE_SUM_WIN formerly known as phytprsn. Find details here about the measurements metadata - units used, codes, etc. LIMNO_PHYTO_PRESENCE_SUM_WIN.csv 10881 1 0 \n column , " https://mcm.lternet.edu/sites/default/files/data/LIMNO_PHYTO_PRESENCE_SUM_WIN.csv DATASET_CODE DATASET_CODE Table Identifier string Table Identifier PHYLUM Phylum Phylum for the specimens observed string Bacillariophyta Bacillariophyta Chlorophyta Chlorophyta Chrysophyta Chrysophyta Cyanophyta Cyanophyta Cryptophyta Cryptophyta Species Species Species of the organism string Species of the organism LOCATION NAME LOCATION NAME The place or location where samples were taken. In this case, it is on Lake Fryxell. string The place or location where samples were taken. In this case, it is on Lake Fryxell. Time Period Time Period The time period when the organism presence was monitored string Winter 1989 The austral winter of 1989 Summer 1990 The austral summer of 1990 Winter 1990 The austral winter of 1990 Summer 1991 The austral summer of 1991 PRESENCE PRESENCE boolean presence, a 0 indicates the organism was not detected at the time period, a 1 indicates the organism presence detected. string FALSE absent TRUE present